Physiological signal processing apparatus and method

Abstract

A method and system for analyzing two related physiological signals to determine a time difference between them. The fundamental frequency components are analyzed to determine a time difference. This approach is robust against varying and different wave 5 shapes, providing a stable and accurate determination of a time difference.

Description

FIELD OF THE INVENTION[0001]This invention relates to the processing of physiological signals, for example for blood pressure monitoring.BACKGROUND OF THE INVENTION[0002]Most, if not all, physiological processes are periodic in nature, where the period itself exhibits some (non-linear) variation. Examples include heart rate, breathing rate and walking gait. These phenomena can be measured using sensors. Depending on the used sensing principle the sensor signals themselves may have different shapes, but the periodicity will remain.[0003]For example, a beating heart generates a periodic electrical signal, normally detected with an ECG, a periodic acoustic signal, normally detected with a stethoscope at the chest, and a periodic pressure wave, normally detected with a stethoscope at the limbs to evaluate blood pressure. Walking generates many periodic acceleration signals, which differ depending on body locations, which differences depend also on the rigidity of the body. There are als...

AI Technical Summary

Benefits of technology

The patent describes a method for automatically detecting a time difference between two signals by analyzing their underlying frequency components and their phase relationship. This approach is robust against varying wave-shapes and provides a more accurate determination of the time difference. The method is particularly useful for non-invasive blood pressure monitoring by accurately and automatically determining the pulse transit time between two signals.

Problems solved by technology

Blood pressure generally rises with aging and the risk of becoming hypertensive in later life is considerable.

Persistent hypertension is one of the key risk factors for strokes, heart failure and increased mortality.

However, these methods are not suitable for performance by the user.

This can be very sensitive to signal noise.

The determination of the two time instants becomes even more cumbersome when the two signal shapes are different.

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